WO2003013795A1

WO2003013795A1 - Air impact screwdriver

Info

Publication number: WO2003013795A1
Application number: PCT/JP2002/008073
Authority: WO
Inventors: Takeo Fujiyama
Original assignee: Max Co., Ltd.
Priority date: 2001-08-08
Filing date: 2002-08-07
Publication date: 2003-02-20
Also published as: JP2003048173A; TW529981B; JP4720042B2

Abstract

An air impact screwdriver (1), wherein a slidable contact nose (12) is fitted to a nose (5) to switchingly operate a contact valve (23) by the contact nose, and an AND circuit for switching between an air motor control pilot valve (39) and a piston control pilot valve (41) is formed of a trigger valve (8) operated by a trigger lever (9) and the contact valve (23), the air impact screwdriver is started for screwing when the contact noise is pushed in and the trigger lever is pulled, and, to further tighten a screw, the contact valve is turned off after the start to stop a screwdriver bit (15) at a bottom dead center and the contact nose is pushed in with the screwdriver bit fitted to the recess in the screw to re-start the screwdriver bit.

Description

Description Air Impact Driver Technical Field

The present invention relates to an air impact driver using a connecting screw, and more particularly to an air impact driver capable of retightening. Background art

2. Description of the Related Art There is known an air impact driver capable of performing a continuous screw tightening operation using a connecting screw in which a number of screws are connected in a belt shape. This type of air impact driver is different from an air impact driver that merely drives the driver bit to rotate, and the driver bit is driven forward by an air cylinder and the driver bit is driven to rotate by an air motor. When the trigger lever is turned on, the air cylinder and air motor are activated and tighten the screw. When the trigger lever is returned to the off position when screw tightening is completed, the driver bit returns to the initial position by the air cylinder, the next screw is fed into the nose of the air impact driver by the screw feed mechanism, and the screw tightening work continues. You can do it. However, if the force that presses the air impact driver against the screw against the screw tightening load is insufficient, the rotating driver bit comes off from the screw head recess and the screw is not completely tightened. May stop in a floating state. In this case, it is necessary to retighten the screw and fully tighten it.However, with a mechanical trigger mechanism with a trigger lever and a contact nose, press the nose again to the head of the screw with the trigger lever pulled. Cannot be re-tightened because the air motor is not configured to restart.

Also, once the trigger lever is returned to the off position, the driver bit returns to the initial position, and when the trigger lever is pulled again, the driver bit advances and rotates in the nose at high speed. Therefore, the tip of the driver bit cannot be engaged with the recess of the screw to be re-tightened, and the driver bit breaks the recess of the screw. Therefore, the air impact driver used for the screw tightening operation cannot be re-tightened, and the re-tightening must be performed using a separate manual driver or the like. Disclosure of the invention

In order to solve the above inconvenience, a technical problem to be solved arises in order to provide an air impact driver capable of re-tightening in addition to a normal screw tightening function. The purpose is to solve.

SUMMARY OF THE INVENTION The present invention proposes to achieve the above-mentioned object, in which a slidable contact nose is attached to a nose of an air impact driver, and a contact valve which is operated to be switched by a slide motion of a contact nose is provided. A pneumatic logic circuit for controlling an air cylinder and an air motor of an air impact driver is provided by a trigger valve operated by a trigger lever and the contact valve, and a small contact nose is pushed in, and a trigger repeller is pulled out to trigger and contact a valve. When the air impact driver is activated, the contact valve is turned off after activation, the driver bit is stopped at the bottom dead center, and the contact noise is pushed in again and the contact valve is pushed. To restart the driver bit at the bottom dead center. The present invention provides an air impact driver configured so that screws already fastened can be retightened. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view illustrating an embodiment of the present invention and illustrating a standby state of an air impact driver.

2 (a) to 2 (e) are cross-sectional views showing operation steps of the impact mechanism. FIG. 3 is a cross-sectional view showing a state where the contact nose of the air impact driver is turned on. 02 08073

FIG. 4 is a cross-sectional view showing a state in which the contact nose and the trigger lever of the air impact driver are turned on.

FIG. 5 is a cross-sectional view showing a state when screw tightening of the air impact driver is completed. FIG. 6 is a cross-sectional view showing a state where a trigger lever of the air impact driver is turned on.

FIG. 7 is a cross-sectional view when the contact valve is opened after the trigger lever of the air impact driver is turned on.

In the figure, 1 is an air impact driver, 5 is a nose, 8 is a trigger valve, 9 is a trigger lever, 12 is a contact nose, 13 is an air cylinder, 14 is a piston, 15 is a driver bit, and 16 is a hexagon. Shaft, 17 is an impact mechanism, 19 is an air motor, 22 is a rod, 23 is a contact valve, 33 is an air motor switching valve, 39 is an air motor control pipe valve, 41 is a piston control pipe valve, 52 is a port valve. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 shows the air impact driver 1, which has an air motor housing 2, a clutch housing 3, a cylinder housing 4, and a nose 5 connected in a row from above, and a housing structure with a grip 6 extending perpendicularly from the clutch housing 3 It has become. Although not shown, an air plug is attached to the end of the grip 6 like a general pneumatic tool, and an air hose is connected to the air plug to supply high-pressure air from the air compressor to the air chamber 7 in the grip 6. I do. A trigger valve 8 and a trigger lever 9 are provided at the base of the grip 6, and the air impact driver 1 is started and stopped by operating the trigger lever 9 to open and close the trigger valve 8.

A known connecting screw feeder comprising a panel offset type air cylinder 10 and a feed pawl 11 connected to its biston rod is provided on the back of the nose 5 (right in the figure). As the feed pawl 11 retreats and advances in conjunction with the operation of the cycle, the connecting screw in the connecting screw magazine (not shown) To 5 The upper right part A in the figure is a cross-sectional view of the trigger valve 8 as viewed from the right, and the lower left part B is a cross-sectional view of the contact nose 12 of the nose 5 as viewed from the left. Is indicated by a chain line.

The piston 14 of the air cylinder 13 built in the cylinder housing 4 has a driver bit 15 mounted on the front (lower in the figure) and a hexagonal shaft 16 mounted on the rear (upper in the figure). The clutch housing 3 has a built-in centrifugal impact mechanism 17, and a hexagonal hole is formed at the center of a driven rotating body 18 (hereinafter referred to as anvil) having a butterfly-shaped horizontal cross section disposed at the center. The hexagonal shaft 16 passes through the hexagonal hole. The rotor 20 of the air motor 19 disposed on the impact mechanism 17 has a center hole larger in diameter than the hexagonal shaft 16, and the upper part of the hexagonal shaft 16 enters the center hole. The piston 14, the driver bit 15, and the hexagonal shaft 16 rotate around the axis together with the anvil 18 of the impact mechanism 17, and can move up and down in the air cylinder 13.

The impact operation by the air motor 19 and the impact mechanism 17 is well known, and the rotor 20 of the air motor 19 is connected to the outer rotor 21 of the impact mechanism 17, and both rotate integrally. As shown in FIG. 2 (a), a lever-type hammer 21a is swingably attached to the outer rotor 21. When the outer rotor 21 starts rotating clockwise in the figure, the hammer 21a rotates in the rotational direction rearward toward the center of rotation due to static inertia, and the rear corner contacts the anvil 18 as shown in FIG. 2 (b). As shown in FIG. 2 (c), the vehicle rides on the convex portion of the anvil 18 and is pushed outward in a direction opposite to the start. As a result, as shown in FIG. 2D, the corner on the front side in the rotation direction rotates toward the center of rotation so as to meet with the projection of the anvil 18, so that the anvil 18 is impacted and rotated. Then, as the anvil 18 rotates, the front corner of the hammer 2 la separates from the anvil 18 as shown in FIG. 2 (e), and the rear corner contacts the anvil 18 as shown in FIG. 2 (b). I do. Hereinafter, the cycle of FIGS. 2 (b) to 2 (e), in which the hammer 21a swings, is circulated at high speed to continuously apply a rotational impact to the anvil 18, and the hex shaft 16 and the biston 14 and the driver bit 15 To rotate.

Next, the contact nose 12 of FIG. 1 will be described. Fits to the outer peripheral surface of the tip of nose 5 Contact Nose 12 can slide upward relative to Nose 5. The contact nose 12 has a rod 22 upward is attached, the tip of the rod 22 enters the rod guide hole of the contactor preparative valve ² 3 provided in the lower portion of the cylinder housing 4 in contact with the stem 24 of Roddogai de bore ing.

Contactor at the center of the front surface of Tonozu 12 mounted stroke adjustment dial ² 5, the stopper ² 6 formed in the nose 5 is located above the stroke adjustment dial 2.delta.. On the back surface of the stroke adjusting dial 25, a cam portion ²⁷ whose radius from the center of rotation changes stepwise (in the illustrated example, eight steps) according to the rotation angle is formed. The panel (not shown) inserted into the hole on the back of the stroke adjustment dial 25, the ball 2δ, and the ball receiving hole 29 arranged in the front of the contact nose 12 form an eight-stage click-top mechanism. The adjustment dial 25 is fixed at a constant rotation angle.

The stopper 26 provided on the nose 5 is opposed to the outer peripheral surface of the cam portion 27 of the stroke adjustment dial 25, and when the contact nose 12 is slid upward, the outer peripheral surface of the cam portion 27 comes into contact with the stopper 26 to make contact. Tonoise 12 stops. As described above, since the radius of the cam portion 27 that hits the stopper 26 differs depending on the rotation angle of the stroke adjustment dial 25, the stroke of the contact nose 12 can be slid upward by rotating the stroke adjustment dial 25 to an arbitrary click position. It can be adjusted in eight steps, which allows you to adjust the screw tightening depth.

Next, a pneumatic circuit and an operation process of the air impact driver 1 will be described. FIG. 1 shows a standby state, in which the stem 30 of the trigger valve 8 is lowered to the closed position by the panel, and the port 31 coaxial with the stem 30 is raised by the panel and the air pressure acting on the lower surface.

The air motor switching valve 33 is connected to the intake port 32 of the air motor 19, the input port 34 of the air motor switching valve 33 is connected to the upper output port 35 of the trigger valve 8, and the upper pipe port 36 is connected to section A. The upper output port 37 of the trigger valve 8 shown is connected to the lower pilot port 38, and the lower pilot port 38 is connected to the air motor control pilot valve 39.

Upper port port 40 of air motor control pipe valve 39 and screw on the left The upper pipe port 42 of the ton control pipe valve 41 is connected to the upper output port 37 of the trigger valve 8 shown in part A.

The upper port 43 of the air cylinder 13 and the front port 44 of the spring-offset air cylinder 10 of the connecting screw feeder are connected to the lower port 45 of the piston valve 41 for controlling the piston. The lower port 46 is connected to a lower port 47 of the trigger valve 8 shown in part A.

The lower port 48 of the contact valve 23 arranged at the lower part of the cylinder housing 4 is connected to the upper port 49 of the piston control pilot valve 41, and the upper port 50 of the contact valve 23 is connected to the air chamber shown in section A. Connected to connection port 51. A lower port 48 of the contact valve 23 and a small port valve 52 disposed adjacent to the contact valve 23 communicate with each other through a gap on the outer periphery of the contact valve 23, and the poppet valve 52 is connected to an air motor control pipe. Open / close the passage 54 leading to the upper port 53 of the cut valve 39. As shown in FIG. 1, when the trigger valve 8 is in the closed position and the contact nose 12 is in the lowered standby position, the high-pressure air in the air chamber 7 flows from the lower port 47 of the trigger valve 8 to the air cylinder 13. It is supplied to the lower air chamber through the lower port 46 and pushes the piston 14 up to the upper standby position.

Fig. 3 shows a state in which the contact nose 12 is pressed against the surface to be screwed in, and the spool of the contact valve 23 is pushed up by the rod 22 of the contact nose 12, so that the upper port 50 and the lower port 48 communicate with each other. The pressurized air is supplied to the air chamber of the piston control pilot valve 41 through the lower port 48, and the spool rises to shut off the upper port 49 and the lower port 45. At the same time, the pressurized air pushes up the port of the port valve 52 through the passage on the outer periphery of the contact valve 23, and the pressurized air is supplied to the air chamber of the pilot motor control valve 39 through the passage 54. However, the spool has been raised to keep the upper port 53 and the lower port 55 shut off.

Subsequently, as shown in FIG. 4, when the trigger lever 9 is pulled, the stem 30 of the trigger valve 8 rises to communicate the upper ports 35 and 37 of the trigger valve 8 with the air chamber 7 and the port 31 The pressure air acting on the lower surface of the air is exhausted downward from around the stem 30 and the port 31 descends, and the air in the lower air chamber of the air cylinder 13 activates the trigger valve 8. Emitted through the atmosphere.

Then, pressurized air is supplied to the input port 34 of the air motor switching valve 33 through the upper port 35 of the trigger valve 8, and the upper pilot port 36 of the air motor switching valve 33 and the pilot port 40 of the pilot valve 39 for air motor control. A pipe pressure is applied to the piston port 42 of the piston control piston valve 41. As a result, the spool of the air motor switching valve 33, the spool of the air motor control pilot valve 39, and the spool of the piston control pilot valve 41 are lowered, and the lower port 48 of the contact valve 23 at the bottom of the cylinder housing 4 Then, the pressurized air is supplied to the upper air chamber of the air cylinder 13 through the piston control pilot valve 41, and the biston 14, the driver bit 15 and the hexagon shaft 16 start descending.

Also, pressure air is supplied to the lower port port 38 of the air motor switching valve 33 through the lower port 55 of the air motor control pilot valve 39, the spool 57 of the air motor switching valve 33 rises, and after the piston 14 descends, the air motor 19 starts. Upon activation, the piston 14, the driver bit 15 and the hexagonal shaft 16 start rotating. When the air motor IS is started, the anvil 18, the hexagonal shaft 16, the piston 14, and the dry pad bit 15 are rotated by the high-speed impact operation of the impact mechanism 17, and the screw is fastened to the object to be screwed.

FIG. 5 shows a state in which the screw is completely tightened. When the screw 14 reaches the lower end of the movable range, the bumper 57 in the air cylinder 13 and the bottom port valve 52 are pushed down. When the port valve 52 is lowered, the pressure air supplied from the air motor control pilot valve ³⁹ to the lower air chamber of the air motor switching valve ³³ is released from the port valve 52 and the lower port of the air cylinder. It is discharged from the trigger valve 8 through 46. As a result, the air pressure acting on the lower surface of the spool 56 of the air motor switching valve 33 decreases, the spool 56 descends, the input port 32 of the air motor 19 and the air chamber 7 are cut off, and the air motor 19 stops rotating.

When the trigger lever 9 is turned off after the screw tightening is completed, the stem ^{30 of the} trigger valve 8 is lowered to the initial position, pressurized air enters the lower surface of the poppet 31 and the poppet 31 is raised, and the lower port of the trigger valve 8 is moved from the air chamber 7. Pressure to lower air chamber of air cylinder 13 through 47 Air is supplied, and Biston 14 rises and returns to its initial position.

Next, a description will be given of the operation procedure and the operation of the air impact driver when retightening a screw that is not sufficiently tightened. When retightening, the screw sent to the nose 5 of the air impact driver 1 must be removed and work must be performed. Therefore, if retightening is performed each time a screw floats, the procedure becomes complicated, so it is efficient to retighten a certain number of screws after tightening, and use the connecting screws in the screw magazine. It is good to do it when you cut it.

First, lift up the air impact dryno with the screw in the nose 5 removed.

Turn on only trigger lever 9 from the initial state shown in 1. As shown in FIG. 6, when the trigger valve 8 is turned on, the upper port ports ³⁶ , 40 of the air motor switching valve 33, the air motor control pipe valve 39, and the biston control pipe valve 41, respectively. , 42 The pilot pressure is applied to 2 and the spools of the pilot valve 39 for air motor control and the pilot valve 41 for piston control are lowered to the open position.

At this time, since the contact valve 23 is in the initial state, the compressed air is not supplied to the piston control pilot valve 41, and the air cylinder 13 remains stopped. Also, since the compressed air is not supplied from the air motor control pilot valve 39 to the lower pilot port 38 of the air motor switching valve 33, the spool 56 of the air motor switching valve 33 is caused by the pilot pressure applied to the upper pilot port 36. The air motor 19 does not start because it descends and shuts off the input port 32 of the air motor 19 and the air chamber 7.

Next, with the trigger lever 9 kept pulled, the contact nose 12 is pressed against the floor or the like, and is pushed in.The spout of the contact valve 23 is pushed up by the opening 22 of the contact nose 12, and the upper port 50 is opened. The lower port 48 communicates, and pressurized air is supplied from the lower port 48 to the piston control pilot valve 41 and the air motor control pilot valve 39 to lower the piston 14.

Then, similarly to the tightening completed state shown in FIG. 5, the piston 14 pushes down the bumper 57 in the air cylinder 13 and the bottom port valve 52, and the port valve 52 descends. As a result, the pressure supply to the piston control valve 41 and the air motor control valve 39 is cut off, and the piston 14 stops at the bottom dead center. Next, the contact nose 12 is separated from the floor or the like, and the tip of the driver bit 15 stopped at the bottom dead center position is engaged with the recess of the target screw head. As shown in Fig. 7, the bumper 57 and the bottom port valve 52 are released from the pressure and rise, and pressure is applied to the piston valve 41 for piston control and the pilot valve 39 for the fan motor control. Air is supplied.

When pressurized air is supplied from the air motor control pilot valve 39 to the lower pilot port 38 of the air motor switching valve 33, the spool 56 of the air motor switching valve 33 is lowered as shown in FIG. 7 due to the pressure receiving area difference between the upper and lower surfaces. The air motor switching valve 33 opens, the air motor 19 starts, the driver bit 15 rotates, and tightens the screw. When the retightening is completed, the screw tightening is completed as shown in FIG. 5, and the driver bit 15 stops.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible within the technical scope of the present invention, and it is natural that the present invention extends to those modified ones.

· This application is based on a Japanese patent application filed on August 8, 2001 (Japanese Patent Application No. 2001-241315), the contents of which are incorporated herein by reference. Industrial applicability

As described above, the air impact driver of the present invention can perform additional tightening in addition to a normal screw tightening function, so that when a screw tightening failure occurs, it is not necessary to perform additional tightening using another driver. Work efficiency is improved.

Claims

The scope of the claims

1. Nose and

Contact 1, nose slidable with respect to the nose,

A contact valve that is switched by the sliding movement of the contact nose,

A trigger valve operated by a trigger lever,

An air cylinder,

A driver bit movably mounted in the air cylinder, an air motor,

A pneumatic logic circuit for controlling the air cylinder and the air motor by the contact valve and the trigger valve;

An air impact driver consisting of

A logic configuration that activates the air impact driver when the contact nose is pushed in and the trigger lever is pulled to switch the trigger valve and the contact valve to the ON position;

After starting, the contact valve is turned off, the driver bit stops at the bottom dead center, the contact nose is pushed in again, the contact valve is turned on, and the driver bit at the bottom dead center is restarted. An air impact driver that tightens the tightened screws.

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